Obtaining tar acids



W. RUNGE.

OBTAINING TAR ACIDS.

APPLICATION FILED FEB. 8, 1918.

1,409,588. Patented Mar. 14, 1922 Non Held 50/,

Fee 'EIr/IcI T MlVE/V TOR fl/J ATTORN Y8 UNITED. STATES PATENT OFFICE.

WALTER RUNGE, OF ORANGE, NEW JERSEY, ASSIGNOR T0 INTERNATIONAL COALPRODUCTS CORPORATION, OF RICHMOND, VIRGINIA, A CORPORATION OF- VIR-GINIA.

- OBTAINING TAR ACIDS.

' Specification of Letters Patent. Patented 11 14 1922 Application filedFebruary 8, 1918. Serial No. 215,992.

To all whom it may concern:

Be it known that I, WALTER RUNGE, a citizen of the United States, and aresident of Orange, in the county of Essex and State of New Jersey, havemade certain new and useful Improvements in Obtaining Tar Acids, ofwhich the following is a specifito 170 degrees C. a light oil fractionis derived; where the maximum temperature is up to 230 degrees C. amiddle oil fraction is derived; where the maximum temperature is up to270 degrees C. a creosote oil fraction is derived, and where the maximumtemperature is up to 360 degrees C. an anthracene oil fraction isderived.

These several fractions are, respectively, referred to as the light oil,middle oil, creosote oil and anthracene oil. Each fraction thus obtainedcontains tar acids and herein applicant is interested only in the lightoil and in the middle oil; The light and middle oils each contain thetar acids above enume rated, to wit, phenol, cresylic acid and thehigher homologues, and which it is the purpose of the present process toquickly and cheaply obtain. Said light and middle oils also containcertain hydrocarbon oils.

According to the process herein described the light and the middleoilscaneach be treated separately, or they can be treated together,dependent upon Whether the hydrocarbon oils of each fraction are toremain separate and thus be recovered separately, or whether thehydrocarbon oils of both fractions may be mixed and as thus mixed toether be recovered.

he light oil, that is the light oil fraction,

and the middle oil, that is the middle oil fraction, contain severaldifferent oils some of which prominent oils are as follows:

Light Oil. Middle Oil. Benzol, Solvent naphtha, Toluol, Heavy naphtha,Solvent naphtha, Neutral oil, Phenol, and Phenol,

Higher tar acids. Cresylic acid, and Higher tar acids.

As previously indicated the present invention is particularly directedto the sepa-.

trated diagrammatically in the sole figure of the accompanying drawing.The phenol, cresylic acid and higher tar acids may be referred to as theM acids orthe tar acids and-may be designated by the symbol MOI-I, inwhich the M represents the base element ofthe tar acids, such as in thecase ofphenol.

where M would represent the radical C H or in the case of cresylic acidWhere M would represent the radical 'C,,H,.CH,', and so on for thehigher taracids. In case of mixtures containing a plurality of acidsthen M represents the base of each acid as, for example, C H,; C H,.CHwhich represent the bases where the mixture had phenol and cresylicacid. The constituents of the light oil group and of the middle oilgroup collectively may be broadly referred to as the aromaticderivatives divisable into acid solutions which are the M acids andnon-acid solutions. The M or tar acid solution includes, as justindicated, the

phenol, cresylic acid and higher tar acids,

while the non-acid solution includes benzol, toluol, solvent naphtha,heavy naphtha and neutral oils.

In the performing of the invention the l soda to form the sodium salt ofthe M or tar acids, as is shown by the following equation;

MOH NaOH H 0 MONa The M or (aqueous solution oi (sodium salt (excess atacids) caustic soda) of tar acid) water) The operationjust referred tois carried out in a tank (an agitator) with. a itation for a peroid of 2to 6 hours and by t is agitation the M or tar acids are brought intointimate contact with the caustic soda in the solution to assist thereaction. At the end of this period the agitation is arrested and thecontents of the tank allowed to settle.

. The solution of the sodium salts of the tar acids, being of highergravity than the nonacid solution, settles to the bottom and thenon-acid solution rises. There is a sharp line of demarkation ordivision where the two solutions meet and due to this physicalcharacteristic 'of the two solutions they may be separated mechanically.This mechanical separation may be effected as by drawing oil thesolution of the sodium salt of the M or tar acids; in other words, theMor tar acid sodium salt solution may be separated mechanically by thisdrawing ofi' operation from the non-acid solution. The M or tar acidsodium salt solution is now treated by brin ing into contact therewithand while under pressure carbondioxide CO either as pure C0,, or as theCO containing any mixed gases as, for example, flue gases. The CO gas ispreferably brought into intimate contact, as by bubbling, that is byblowing jets of CO in the aqueous solution containing the sodium salt ofthe M or tar acids (the MONa.)

The reaction which takes place is as follows:

. 2MONa 00 H O ZMOH N a OO (sodium salt of (carbondi- (water) (free taracid) (sodium carbon- M or tar acid oxide) (light liquid) ate inSOllltlOl]. in solution) (carbonic acid) in excess H2O) The solution ofsodium salt of M or tar acids is under substantially super-atmosphericpressure, preferably of 100 pounds, during the time the reaction justdescribed is taking place. Other methods than bubbling for bringing'theCO gas into intimate contact with the M or tar acid sodium salt solutionmaybe employed.

It will be understood, 'however, that an important feature of thepresent invention is the employment of said pressure which expedites theultimate reaction. During the process the pressure is maintainedsubstantially super-atmospheric, preferably at 100 pounds, by supplyingadditional Ct) under pressure to replace the CO absorbed as the reactionprogresses. If CO is supplied by the introduction of flue gas the inertgases that necessarily constitute a part of flue gas are left andcollect in the chamber'as the reaction progresses. These inert gasesthat collect are withdrawn as desired, or when they become too great involume. As the M or free tar acids (MOH) are relatively light or of lowspecific gravity and as the aqueous solution of sodium carbonate isheavy or of high specific gravity the M or tar acids will be readilyseparated from the aqueous sodium carbonate solution. It will,therefore, be seen that the sodium carbonate solution separates, due togravity, from the M or tar acids, thus facilitating mechanical searation.

ferring to the drawing, it will be seen (heavy liquid) that thereinthere is illustrated diagrammatically a form of apparatus which can beemployed in' the realizing of the invention.

In this apparatus there are shown con-' nected tanks A and Brespectively, the latter of which is constructed so that substantiallysuper-atmospheric pressure can be maintained while the operation thereinis being carried out. I

' Thetank A has an outlet pipe C provided with valve controlled pipes Dand E extending in opposite directions. The pipe D is controlled by pipeE is controlled by a hand-valve G. The t nk A has in the lower portionthereof a perforated pipe or coil H to which compressed air is suppliedby the valve 'controlled pipe K. The perforated pipe or coil H is a partof the mechanism employed to effect an agitation of the liquid contentsof the tank when .it is desired that the agitation be carried out. Thismechanism in fact provides air agitation, as it is known in the arts,and may be referred to as air agitating means. With the valves F and Gclosed there is first placed in the tank A the reuired aqueous solutionof caustic soda tNaOH) and this is followed by the insertion of theproper quantity of light oil, or middle oil, or both-of these oils,dependent upon whether the light oil, the middle oil or both of the oilsis or are to be treated and until agitation is actually started theaqueous solution of caustic soda will remain at a hand-valve F while thethe bottom-and the oil or oils will float on the top of this aqueoussolution. \Vhether or not the light oil or the middle oil, or both ofthese oils is or are introduced is dependent upon the source from whichthe ultimate M or tar acids are. to be obtained. The oils and thesolution in the tank are subjected to agitation by the air agitatingmeans just described; they are also preferably heated as willhereinafter appear. As the reaction proceeds there is a tendency forheavy particles in the solution to settle to the bottom of the tank andtherefore there is provided a pumping mechanism L in the form of anejector having a suction pipe L extending from the lower portion of thetank and a delivery pipe L? emptying into the upper portion of the tank.As the pumping mechanism L is in the form of an ejector dependent forits operation upon steam flowing inwardly through the valve controlledpipe L and being delivered from the nozzle L of the ejector, saidejector can be employedto perform two functions: (a) to serve purely asa pump to convey or transfer the contents from the lower portion of thetank to the upper portion of the tank and (b) to serve as a means tosupply heat during the period the reaction is taking place. It isdesirable to maintain the solution hot While the reaction is takingplace and it will be manifest that the ejector supplies this heat fromthe incoming steam. However, heat can be supplied in other ways, as byinserting an independent heating coil in the lower portion of the tank,or by providing a heating means exterior of the tank. Or, the heat couldbe supplied by air heated prior to passing through and from the coil H.In place of the ejector there could be'employed a purely mechanicalpump. The pump or ejector L assists in the agitation, as is obvi-v ous,due to the transferring of the solution from the lower portion of thetank to the upper portion thereof. The reaction which takes place inthis tank generally requires from 2 to 6 hours. Then the reaction iscompleted the contents of the tank are comprised of the non-acidsolution which is relatively light and the sodium salt solution of the Mor tar acids which is relatively heavy, the latter of which is marked onthe drawing MONa. When the settling operation is completed a sharp lineof demarkation exists, at X, between the non-acid solution and the MONasolution.

With no pressure in the tank B-viz. with no pressure substantiallyabove-that of the atmospherethe MONa solution can be permitted to flowdirectly into the tank B by merely opening the valve G and in this waythe mechanical separation of the MONa solution from the non-acidsolution is completed. When the MONa solution is completely withdrawnthe valve G is closed and thereafter by opening the valve F the nonacidsolution can be withdrawn from th tank A.

The tank B has an outlet pipe 0 controlled by a hand-valve N. Within thetank B there is a mechanical agitator P. having a shaft extendingthrough a' packing Q and suitably driven as by bevel gearing R. In thelower portion of the tank B there is a perforated pipe or coil S towhich CO is supplied through a valve controlled pipe T. From the upperportion of the tank there extends a valve controlled pipe U. Nosubstantial pressure exists in the tank B, as will hereinafter appear,when MONa. is being supplied -to the tank through pipe E. The MONasolution, as has been previously pointed out, is an aqueous solution.\Vhen the reaction is being carried out in tank B the CO is suppliedunder substantially super-atmospheric pressure, as by the compressor Tthrough pipe T to the perforated pipe or coil' S. As the valve G in pipeE and valve in pipe U are closed during the time the reaction is takingplace the CO is supplied in such a manner that the pressure within thetank is maintained at approximately 100 pounds per square inch. Thepacking Q is constructed so that 'said pressure can be maintained.

As has been reviously pointed out the water of the solution and the COunite to form carbonic acid which in turn reacts with the MONa and thusthere is a continuous absorption of the CO tending to reduce thepressure within the tank B. Therefore, CO must be supplied eithercontinuously or intermittently to replace the CO used up by thereaction. The absorption of the CO tends to reduce the pressure and theCO is supplied not only to furnish the requisite O necessary for thechemical reaction but also to maintain the desired approximate 100pounds pressure-substantially super-atmospheric pressurewhich expeditesthe reaction. During the time the reaction is taking place the agitatorP is operating and as the CO is introduced under substantiallysuper-atmospheric pressure through the perforated pipe or coil S it willbe observed the CO is bubbled into the solution being treated within thetank B. The mechanical agitating and the bubblingwhich is alsoagitating-bring the CO into intimate contact with the MONa salt in thesolution and with the pressure maintained substantiallysuper-atmospheric the reaction within the tank B is effected in arelatively short space of time. If the CO supplied is derived from fluegases pumped under pressure into the tank B there will be a collectionof inert gases in the upper portion of the tank B. These inert gases canbe withdrawn intermittently or continuously by opening thevalve in thepi e U. When the reaction is completed the 60, supply is shut off, theagitator P is stopped, and the contents of the tank B are allowed tocome to rest and settle. The M or tar acids (MOH) which have been freedas the result of the reaction are relatively light and they collect inthe upper portion of the tank. The sodium carbonate (Na,CO

I which is absorbed in the water of the solution together form what maybe called the sodium carbonate solution and this solutionbeingrelatively heavy settles or collects in the lower portion of thetank B. When the settling is completed there is a shar line ofdemarkation indicated by the line be tween the M or tar acids and thesodium carbonate solution. By opening the valve N the sodium carbonatesolution is first withdrawn from the tank B; subsequently the M or taracids can be withdrawn. In this manner the complete mechanicalseparation of the sodium carbonate solution and the M or tar acids canbe readily effected and the M or tar acids recovered. The valve N isleft open until the pressure within the tank B is reduced whereby a newsupply of the MONa salt can be introduced into the tank B for treatmentand the cycle of operations just described repeated.

As previously indicated an important feature of the present inventionresides in the maintaining of the MONa solution under substantiallysuper-atmospheric pressure while it is being treated with CO but it willbe pointed out that the expression maintained at substantiallysuper-atmospheric pressure as employed herein is not to be construed asnecessarily meaning that the pressure must be maintained at somedefinite amount as, for example, 100 "pounds throughout the entire timereaction is taking place, but it is to be broadly construed as coveringa situation wherein the pressure may vary somewhat during the reactionbut one in which the ressure is maintained at all times substantlallysuper-atmospheric.

quired to accomplish said reaction is often as long as 24: hours or evenlonger.

According to my process the MOH acids can be recovered orreclaimedseparate d from the rest of the ingredients of a tar.

fraction or tar fractions as the case may be in much less time than byany process heretofore known or employed.

The improvements herein set forth are not limited to the mode ofoperation, or to the process, construction and arrangement shown anddescribed for they may be employed in various ways, forms andmodifications without departing from the spirit and scope of the.invention.

IVhat I claim is:

1. The obtaining of a tar acid from its salt by the method whichconsists in intimately bringing into contact with each other carbondioxide and said salt while in the presence of water and under a substantially super-atmospheric pressure approximating 100 pounds persquare inch, which super-atmospheric pressure is maintained until thereresults free tar acid, and

subsequently separating said free tar acid from the rest of thesolution.

2. The obtaining of tar acids from their salt by the method whichconsists in intimately bring into contact with each other flue gas andsaid salt while in the presence of water and under a maintained pressureapproaching 100 pounds per square inch until the tar acids .areliberated, and subsequently separating said tar acids from the rest ofthe solution.

3. In the obtaining of tar acids the method which consists in subjectingan aqueous solution of sodium salt of tar acids, when underapproximately 100 pounds pressure per square inch in a closedreceptacle, to the hubbling action of CO until tar acids are freed, andsubsequently separating said tar acids from the rest of the solution.

4;. In the obtaining of tar acids the method which consists insubjecting an aqueous solution of sodium salt of tar acids, when under amaintained pressure in a closed receptacle and which pressureapproximates 100 pounds per square inch, to the bubbling action of fluegas until there result tar acids in free form, and subsequentlyseparating tar acids when in said free form from the rest of thesolution, the inert gases which collect at the top of thereceptaclebeing withdrawn therefrom as desired.

This specification signed and witnessed this 7th day of February, A. D.1918.

WALTER RUNGE. Signed in the resence of:

EDWIN A. ACKARD, G. MCGRANN.

